Originally Posted by
genec
I believe this study has been previously rejected by the anti-facilites crowd based on their perception of lack of thorough studies, lack of data, and that Doctors have no idea of how to ride bikes or do traffic engineering.
Of course what do all these folks know about facilities, eh?
Kay Teschke, Melody Monro, and Hui Shen are with the School of Population and Public Health, University of British Columbia, Vancouver, Canada. M. Anne Harris is with the Occupational Cancer Research Centre, Toronto, Canada. Conor C. O. Reynolds is with the Liu Institute, University of British Columbia. Meghan Winters is with the Faculty of Health Sciences, Simon Fraser University, Burnaby, Canada. Shelina Babul is with the BC Injury Research and Prevention Unit, Vancouver, Canada. Mary Chipman, Michael D. Cusimano, and Lee Vernich are with the School of Public Health, University of Toronto, Toronto, Canada. Jeff R. Brubacher and Garth Hunte are with the Department of Emergency Medicine, University of British Columbia. Steven M. Friedman is with the Emergency Department, University Health Network, Toronto, Canada. Peter A. Cripton is with the Department of Mechanical Engineering, University of British Columbia.
Read More:
http://ajph.aphapublications.org/doi...PH.2012.300762
While Genec is attempting irony when rhetorically asking "what do all these folks know about facilities, eh?", the question is eminently worth considering. I have read only the free abstract; haven't paid for the full paper. But the abstract states that each crash was linked to the full trip that the cyclist was making. For each crash, another location along that trip was randomly selected for comparison. I think that that makes no sense. I think that the study must have aggregated all trips and locations to get many crash sites and many non-crash sites, and worked the probabilities from there.
I suggest several grounds for skepticism. Are the sites properly categorized? Maybe so, maybe not, but these investigators certainly are not qualified by their professions to do so. Are the crash sites properly categorized, not by the location of the crash but by the course that the cyclist was following? For example, were crashes where paths (of any kind) intersected roads categorized by whether the cyclist had been using the path, or were they classed as roadway crashes because they occurred on the roadway? The abstract suggests that the facility type was the cause of whatever crash probability the data disclosed, in that the investigators suggested that similar facility designs from elsewhere be made more frequent here. That's not necessarily correct, because in the USA and Canada there is considerable before-the-fact decision making in determining whatever facility type be installed; facilities often get installed in the safer locations because doing so is easier there than elsewhere. None of these considerations are considered in the field of public health and medicine; they are not only traffic engineering considerations, but constitute a distinct specialty in the bicycle traffic engineering aspect of general traffic engineering.
So, you see, while Genec thought that he was asking a nonsense question, just for effect, his question raises very real concerns about the accuracy of the paper.